Pendant la guerre Américaine contre le Vietnam, les Américains ont utilisé beaucoup d'armes chimiques. En plus des produits chimiques comme le napalm qui a brûlé et a mutilé beaucoup de personnes, les Etats-Unis ont utilisés des agents chimiques pour défeuiller une grande partie de la terre du Vietnam du Sud comme manière de priver les armées du nord et leurs alliés de nourriture venant du sud et de l'abri de la couverture des forêts.

L'AIJD s'est opposé à l'utilisation de ces produits chimiques au moment de la guerre en raison de leur utilisation aveugle contre des civils aussi bien que de leurs effets toxiques potentiels sur les personnes et l'environnement.

L'agent orange était de loin le plus employé de tous les défoliants, bien qu'il y ait eu beaucoup d'autres agents, par exemple l'agent blanc, l'agent pourpre, l'agent rose, et l'agent bleu. Ces agents ont obtenu leurs noms, non pas de la couleur du produit chimique mais de la bande peinte sur les barils dans lesquels ils ont été embarqués.
La plupart de ces agents ont contenu divers proportions du mélange de deux composés organiques : 2,4,D et 2,4,5-T. L'agent orange était un mélange 50-50 de ces composés. Bien que créé dans des « conditions de laboratoire » la fabrication d'un des produits chimiques--2,4,5,-T-- contient une dioxine comme impureté. Cette dioxine est l'une des substances les plus toxiques que n'ait jamais connues l'homme. Elle est connue pour causer des malformations de naissance chez les animaux à très petites doses, par exemple une part par trillion.
Les agents utilisés au Vietnam n'ont pas été faits en en laboratoire, ils ont été fabriqués très hautes températures et à une cadence élevée. Le résultat de ce mode de fabrication était d'augmenter le niveau de dioxine. Certains contenais plus de 40 parts par million.

Des millions de litres de ces agents ont été pulvérisés au cours des périodes 1961 1971 par les Etats-Unis et ayant pour résultat des centaines de kilo de dioxine étant pulvérisée, avec 12% de la région terrestre et plus de 4 millions de personnes vietnamiennes exposées à ces agents. On estime que plus de 600.000 Vietnamiens souffrent actuellement de maladies provoquées par l'agent orange et de défauts de naissance qui se révèlent maintenant dans la troisième génération. Il y a beaucoup « de points chauds " où les niveaux de dioxine dans le sol l'eau et les corps des populations dans ces secteurs sont tout à fait élevés. Ces points chauds se situent dans et autour des bases militaires abandonnées par les USA.

Vers la fin des années 90 l'Association des Juristes Vietnamiens, par leurs représentants à l'AIJD a commencé à signaler des problèmes significatifs de la maladie et des défauts de naissance parmi les populations exposées qui ont été attribuées à la pulvérisation de l'agent orange. En 2001, quand le congrès des avocats de l'Asia Pacific (COLAP) III a été tenu à Hanoï, une demande formelle a été faite à l'AIJD d'explorer la possibilité d'intenter une action judiciaire contre les compagnies chimiques qui ont fabriqué ces produits.

In 2002 a working group of lawyers in the United States was developed through IADL affiliate, the National Lawyers Guild, to explore the possibility of bringing an action against the chemical companies under the Alien Tort Statute as well as for domestic torts of product liability.

The Alien Tort Statute would allow the Vietnamese victims to sue for damages for "violations of the laws of nations or treaties". This statute was passed in 1789 and very rarely used. It was resurrected in 1980 when a case was brought to collect damages in a case involving torture, where the torturer was found in the United States. After that case, known as Filartiga v Irala Pena, many cases had been brought against individuals and corporations under the Alien Tort Statute for such things as extra judicial killing, rape as an instrument of war, forced labor, and the like.

On January 30, 2004 suit was filed in New York city against 37 chemical manufacturers who produced agent orange for the US government for use in Vietnam. The plaintiffs included the Vietnam Association for the Victims of Agent Orange/Dioxin (VAVA) and several individuals who were ill or had suffered illnesses due to exposure to agent orange. The primary claim was that the use of agent orange violated the Hague Regulations of 1907 which prohibited the use of poison or poisoned weapons in war.

The legal team which filed the action included IADL secretary general Jeanne Mirer, NLG members Constantine Kokkoris, Jonathan Moore, and William Goodman from New York and Kathleen Melez from Los Angeles. The team was later joined by Frank Davis, Johhny Norris, Stan Morris, and Jonathan Cartee from Birmingham Alabama. The members from Birmingham had been successful in bringing major toxic tort, products liability, cases against several of the defendant chemical companies in the past.

The case was assigned to Judge Jack Weinstein. Judge Weinstein was the judge who had heard cases filed by the United States veterans of the war in the early 1980's who had sued for damages due to their own injuries as a result of their exposure to agent orange. A multi-district litigation order required all cases involving Agent Orange be assigned to Judge Weinstein.

The original US veteran’s cases were settled in the late 1980's and payment was made to a large class of US veterans. In the mid 1990's another group of US veterans sued again and their case was still pending at the time the case for the Vietnamese was filed in 2004. Thereafter the cases of the US veterans and the Vietnamese victims were virtually consolidated. That is, the motions to dismiss the cases filed by the defendants were heard on the same day. The decision of Judge Weinstein to dismiss both cases occurred at about the same time. The appeals of the cases were heard on the same day and the decisions affirming the dismissals were issued on the same day, February 22, 2008.

Both Judge Weinstein and the Court of Appeals rejected the arguments of the plaintiffs that agent orange which was laced with dioxin was a poisoned weaponed which violated the Hague Regulations. Both decisions held that these agents were mere herbicides which were aimed a plants not people, and no rule of international law in existence during the war prohibited the use of herbicides. By refusing to recognize that the presence of dioxin fundamentally shifted these chemicals from anti-plant agents to poisonous weapons, both Judge Weinstein and the court of appeals were able to justify ruling against the Vietnamese victims. . Also, after the case had been filed the US Supreme Court had decided a case called Sosa v Alvarez-Machain which more narrowly interpreted the Alien Tort Statute. Both court’s used the opinion in Sosa to support their rulings that the use of these weapons did not violate any treaty or universally recognized customary international law.

The case of the US veterans was also dismissed on the grounds that the chemical companies were protected from suit under the government contractor defense. This defense extends the shield of immunity which the state has under "sovereign immunity" to contractors who provide products to the government as long as they disclose to the government information about the dangers of the product. The US veterans claimed the chemical companies did not disclose what they knew about the dangers of dioxin to the government. The Vietnamese plaintiffs relied on the arguments made by the US veterans to support their domestic law claims so that the loss in front of Judge Weinstein and the court of appeals by the US veterans applied to the Vietnamese plaintiffs as well

All of the The court documents up to the most recent decision of the U.S court of appeals for the second circuit are located on the website of the Fund for Reconciliation and Development, www.ffrd.org.

While this case has been pending the mass movement to educate the public of the legacy of the use of these chemical weapons has proceeded apace. In the US the IADL and NLG cooperate with the Vietnam Agent Orange Relief and Responsibility Campaign, (VAORRC) which is a coalition of many community and veterans groups, primarily Veterans for Peace (VFP). Their website is www.vn-agentorange.org. The IADL also cooperates with the War Legacies project of the Fund for Reconciliation and Development which is raising funds directly for the victims.

On June 18, 2007, the date of the oral argument in the court of appeals, the IADL sponsored a day of solidarity with the Vietnamese victims of Agent Orange. On that day around the world, IADL affiliates issued statements calling for support for the Vietnamese victims of agent orange.